amistre64

2 years ago

Worst worded question to date:
A brick is thrown upward from the top of a building at an angle of 25degrees to the horizontal and with an initial velocity of 15m/s. If the brick is in flight for 3 seconds, how tall is the building?

only the velocity in vertical direction is of use here
\[V_v= 15 \sin 25 \]
now let's find the time it takes the velocity in vertical direction to get to 0
and the distance it covers|dw:1346855419638:dw|
let the height be h1 and time be t1
here acceleration due to gravity=10 m/s^2 in downwards direction so -10
\[v-u=at\]
\[0-V_v=-10*t_1\]
we could find t_1 from here
\[v^2-u^2=2as\]
\[0-(V_V)^2=2*-10*h_1\]
h1 from here
now the remaining time it takes to reach ground
3-t1
using this we could find h2
building's height is h2-h1